Aug 3, 2015

Magnesium diboride superconductors can lower the cost of wind turbine generator coils by over fifteen times

In January 2001, it was announced that MgB2 (magnesium diboride), a compound that was well known to chemists, was superconducting up to 39 Kelvin. Building on this discovery, Hyper Tech was formed in 2001 to use the compound to create a high-performing, low cost superconducting wire. Hyper Tech developed and patented a continuous tube forming and filling (CTFF) process for the manufacturing of a powder metallurgy-based MgB2 superconductor wire.

Hyper Tech is the world leader in manufacturing and R and D of magnesium diboride and niobium tin superconducting wire and integrated products. Hyper Tech's innovative, patented wire drawing process enabled the company to be the first to manufacture viable long-length MgB2 wire. Hyper Tech has consistently integrated this technology into transforming products benefiting from superconducting materials. Superconductors carry high current with near zero ohmic loss. In coil form, such as in an electromagnet, a charged and closed loop can carry current, and hence magnetic field, for long periods of time (of the order of months to years depending on the detail design). This makes a superconductor ideal for high field magnets. It is commonly used in MRI and nuclear magnetic resonance (NMR) systems throughout the world. Hyper Tech is well equipped to produce two wire formed superconductors: MgB2 and Nb3Sn.

Hyper Tech's 41,000-square-foot facility contains the equipment necessary to manufacture MgB2 superconducting wire of varying diameters and lengths. A team of engineers, scientists and technicians has been assembled to develop and produce the superconducting wires and related products including superconducting coils for various applications. Hyper Tech is marketing MgB2 superconductor wires for MRI applications and has cooperative relationships with several companies to apply MgB2 superconductor wire to MRI devices. This commercial market has allowed Hyper Tech to lower the wire production cost to be economical for power systems applications as well (e.g., FCLs and wind turbines).

A solenoid coil fabricated in 2012 was wound with 590 meters of MgB2 multifilamentary wire. This coil achieved a peak bore field of 4.6 Tesla at 4 Kelvin and 2.2 Tesla at 20 Kelvin.

The advantage of MgB2 magnets when compared with permanent magnets is the possibility of achieving magnetic field strengths of considerably more than 0.4 Tesla (to 1.5-2.0 Tesla) with a lower initial capital equipment cost and lower life-cycle cost. Also, higher field strengths and larger zones of homogeneous magnetic field can be achieved with MgB2 superconductor than with permanent magnets. Compared with superconductors that operate at lower temperatures, such as NbTi and Nb3Sn, the life-cycle costs of MgB2 coils are lower because of their higher operating temperature and lower associated refrigeration costs during operation. In the on-going effort to eliminate liquid cryogen from equipment, the temperature tolerance of MgB2 better suits it for dry operation using only a cryocooler and conduction cooling.MgB2 conductors have many distinct advantages when compared with high temperature ceramic conductors. Since the wire can be configured in either round or rectangular cross sections, MgB2 adds flexibility in coil design and fabrication. MgB2 is lighter weight and can be produced at a lower cost than the high temperature ceramic BSCCO or YBCO-coated superconducting tape conductors when operated in the 20 Kelvin range. MgB2 wire is versatile in that it can be sized (e.g., to custom amperage and engineering current density) for targeted coil dimensions and performance. MgB2 wire behaves more like a metal superconductor with regard to persistent current type coils unlike high temperature superconducting tapes.

Up to 200 kilometers of coil is needed to generate electricity in wind turbines and with current technologies, that coil would cost between AUS$3-5 million to manufacture. The same length of magnesium diboride superconducting coil costs AUS$180,000 and that figure could reduce dramatically as magnesium diboride becomes less and less expensive.

Hyper Tech Research magnesium diboride coil is about AUS$1 per meter to manufacture.

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